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Stanford Report, March 15, 2000

'Biological bypass' may improve blood flow in legs  


Stanford University Medical Center researchers are asking volunteers to help determine whether a common food supplement can improve blood flow to diseased leg arteries, thus alleviating pain, difficulty walking and other symptoms of clogged blood vessels.

"Preliminary studies have shown that the amino acid L-arginine may restore blood flow to a leg that suffers from insufficient blood supply because of blood vessel blockages, but we hope this two-month study will give us more conclusive information," said John P. Cooke, MD, associate professor of medicine (cardiology), and leader of the National Institutes of Health-sponsored study at Stanford University.

Cooke said remedies for intermittent claudication, the pain caused by lack of circulation to the leg, are limited. Exercise has proved to be the best remedy for the largest number of patients, he said, while surgery can sometimes relieve symptoms.

"The current drug therapy is not ideal. Pentoxifylline is not very effective, and [another newer medication], cilostazol, has frequent side effects," Cooke added.

Cooke noted that L-arginine is normally present in the Western diet but in very small quantities that are insufficient for people with poor circulation. It is found in soy protein, nuts and legumes. It is also available as a diet supplement without prescription, but the correct dose and long-term effects need further study. He said L-arginine is expected to stimulate the body to produce nitric oxide, relaxing the blood vessels and increasing blood flow. There is also some evidence that L-arginine plays a role in angiogenesis, the formation of new blood vessels. By promoting new blood vessel growth, said Cooke, L-arginine may essentially induce "biological bypasses," reducing the need for bypass surgery.

Volunteers for the current study should be diagnosed with intermittent claudication and able to make two visits to Stanford Medical Center for physical exams. Seventy-five percent of the volunteers will receive L-arginine in varied doses, while the rest will receive a placebo. Cooke said all patients will be provided with information about intermittent claudication and their own condition.

To volunteer or to receive more details, call Roberta K. Oka, project coordinator, at (650) 723-4064.

Cooke invented the HeartBar, a commercially available nutrient bar that contains L-arginine and a variety of vitamins and other ingredients designed to improve blood flow to the limbs. He is founder and part owner of Cooke Pharma, Inc., which manufacturers the HeartBar. SR